The present invention relates to a method and a device for converting a production plant provided with a plant central control unit and consisting of several machines that are respectively provided with a separate control unit and are used for the post print processing, wherein different production orders are processed successively with said method in order to turn partial or semi-finished products into finished print products.
During the post print processing operation, partial products such as individual sheets containing a plurality of pages for the finished print product are turned with the aid of several temporally successive processing steps into finished print products, e.g. magazines, catalogs, books, newspapers or similar products. This type of processing takes place on a plurality of machines for the post print processing which are linked together to form a production line. In the process, post print processing machines designed for producing the finished products take over the partial or semi-finished print products from an upstream-arranged post print processing machine and, following the processing, transfer these to another post print processing machine.
Traditional printing presses are for the most part operated “offline,” meaning the printing press is operated independent of the post print processing. Individual sheets are produced in the printing press and are then stored temporarily. As soon as all sheets required for collating a book are printed, the post print processing operation can take place.
With digital printing presses, it is possible to sequentially print the sheets of a book and thus form sheet packets that form a book. Digital printing presses of this type are frequently operated “inline” with the post print processing operation, meaning the digital printing press is linked to the post print processing to form a joint production line.
A book binding plant can be used, for example, for the post print processing operation. A plant of this type generally comprises a collating machine for gathering a number of print sheets that form a finished print product, a binding machine, such as an adhesive or perfect binder, a removal device which can contain a curing section for the adhesive if a perfect binder is used, a cutting machine for trimming the side edges of the partial product received from the perfect binder, if applicable along three sides, and a stacking device for stacking the print products. Additional machines for the post print processing can also be used, such as an inserting machine for inserting loose products into the bound print products.
In part, production lines are long and complex and are composed of the aforementioned post print processing machines. The sequence in which the post print processing machines are arranged is predetermined by the further processing that is required for the partial products. Depending on the finishing process, the partial products pass through all or only some of the post print processing machines and are processed therein. A post print processing machine which is not involved in the active processing can only be used for the transport of the partial products.
Production lines of this type are normally operated by several persons. In case of a change in the production order, the operators in charge convert the machines for the post print processing while auxiliary personnel removes or supplies corresponding partial products. The post print processing machines are generally configured for any production order to be processed in a production plant and are set up according to a production order in such a way that the processing of the partial products can take place as specified.
Alternatively, a single operator can also successively convert each post print processing machine of a production plant. Once the operator has converted the last one of the post print processing machines, the new production order can be started. However, this action involves a long conversion period for the total production plant and consequently requires a long standstill time for the upstream arranged digital printing press. To convert the production plant between production orders, it is initially operated without load and is then converted.
The digital printing technology provided the option of combining the printing process with the post print processing operation in a joint production plant and thus made it possible to operate the complete process “inline.” A reduction in the number of operating personnel required for a production plant of this type therefore results in an increase in the economic efficiency of these types of digital print production plants.
In many cases, the digital printing press can be converted much faster than the following machines for the post print processing. If the conversion time for the post print processing operation takes only insignificantly longer than the conversion time for the digital printing press, then the digital printing press can be restarted immediately after its conversion, wherein the partial products are transported to a buffer section during the conversion of the post print processing machines. A relatively long conversion time for the post print processing operation, however, results in a poor utilization of the digital printing press.
The post print processing machines are generally controlled with the aid of separate machine control units which communicate via standardized bus interfaces. These machine control units can additionally be linked to a plant central control unit. An arrangement of post print processing machines is known from the prior art publication WO2012048435 A1 for which a plant central control unit is connected to local machine control units. The machine control units determine the required conversion times for the respective post print processing machines from the control data received from the central control unit. The computed conversion times are then transmitted by the individual machine control units to the plant central control unit which, in turn, determines gaps in the conveying goods for the complete plant. Accordingly, the individual machine control units do not provide direct feedback of the current setup parameters for the respective post print processing machine to the plant central control unit.
A production plant for the post print processing, comprising two production lines, is also known from the EP 1777078 A1, wherein these production lines are respectively composed of post print processing machines. The two production lines in this case contain parallel-switched as well as jointly operated post print processing machines. With this production plant, some of the post print processing machines can be operated without load and can be converted for a new production order while other, parallel switched, machines for the post print processing are still processing the current production order. The disadvantage of the described arrangement is that a relatively high number of redundant post print processing machines are required for this, thereby resulting in relatively high total costs for the production plant.
The DE 102010015128 A1 discloses a single post print processing machine which is embodied as perfect binder and comprises a plurality of continuously circulating clamps of a transporting device for the fast conversion to different formats of successively processed orders. For this, a cycle time of the post print processing machine is extended, corresponding to the required format change for the following production order to be processed, by leaving some clamps of the transport arrangement for the partial products empty, such that more time is available for the pre-adjustment of processing stations of the perfect binder to conform to the following production order.